The invention relates to a keyboard for introducing data of the digital type or logical instructions into an instrument for processing or utilising such data such as office calculators or pocket calculators, keyboard arrangements for composing telephone numbers or any other pushbutton arrangement providing an instantaneous return and intended to establish electrical contacts which transmit an order or information.
Known keyboards of this type even if they provide satisfactory performance are generally of a relatively complex construction which places them in a high price level, causes them to occupy more volume than is desired and does not favor their utilization for arrangements where miniaturization is desired.
Swiss Pat. No. 545 991 has, however, suggested that in order to avoid such inconvenient features, a network might be employed comprising a single conductive plate in which elastic tongues have been cut out, these tongues forming moving contact organs having a snap action. The contact of a tongue with a conductive base corresponding thereto is established by an associated pushbutton. The proper functioning of this arrangement requires that such tongues be arched by a permanent deformation after they have been cut out and tempered, thereby causing their manufacture to be relatively complex and expensive. The arrangement of this network as a single piece has the disadvantage that in case of the failure of a single contact the entire network is rendered useless and must be replaced.